Hierarchical Ni-Co-S@Ni-W-O core–shell nanosheet arrays on nickel foam for high-performance asymmetric supercapacitors

He, Weidong; Liang, Zhifu; Ji, Keyu; Zhang, Jiayi; Zhai, Tianyou; Xu, Xijin

doi:10.1007/s12274-017-1757-2

Cited by 104 publications

(47 citation statements)

References 56 publications

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“…Hybrid supercapacitors (or hybrid batteries), composed of a battery‐type electrode and a capacitive carbon‐based electrode, are attracting extensive attention recently, because they combine high energy density of batteries and both high power density and long life span of supercapacitors . Over the past years, many hybrid supercapacitors have been developed on the basis of activated carbon (AC), such as Ni(OH) 2 //AC, NiO x //AC, CoO x //AC, MnO 2 //AC, LiMn 2 O 4 //AC, PbO 2 //AC, etc.…”

Section: Methodsmentioning

confidence: 99%

Robust Negative Electrode Materials Derived from Carbon Dots and Porous Hydrogels for High‐Performance Hybrid Supercapacitors

et al. 2018

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3-5 folds or more amounts of carbon materials are required to fill the capacitance gap between the positive/negative electrodes, which finally restrict the whole energy densities of the devices. To improve electrochemical capacitances of carbon materials, three main strategies have been investigated thoroughly: enlarging specific surface areas, [19] constructing porous structures, [20,21] and introducing pseudocapacitive reactions. [22] But each strategy is not perfect. When the surface areas and the pore volumes are improved, the tap densities of electrodes will be reduced. Moreover, enhancing pseudocapacitance by modifying too many functional groups will decrease the whole conductivity and stability of electrode materials. [23] In the present work, we suggest a new concept of building electron-rich regions on the electrode surface, so as to adsorb more cations and accelerate the charge transfer. As a result, the capacitance of carbon materials will be increased reasonably without sacrificing the density, conductivity, and stability of the whole electrode. However, this idea brings a new challenge because the desired groups with abundant electrons (like phosphate groups) are usually difficult to be modified on the carbon materials. In order to resolve this problem, we used carbon dots (CDs, sub-10 nm) [24,25] with desired groups as the guest, and the commercial polyacrylamide (PAM) hydrogel as the host. After calcination on the host-guest composites, we obtained new carbon frameworks which have abundant electron-rich regions, large surface areas, and appropriate porous structures in the meantime. The optimal sample exhibits a specific capacitance up to 468, 510, and 438 F g −1 in alkaline, acidic, and neutral electrolytes, respectively. When it is fabricated into a hybrid supercapacitors with the positive electrode material Ni(OH) 2 /CNTs using an alkaline electrolyte, the mass ratio of positive/negative electrodes is less than 2, an energy density over 90 Wh kg −1 is realized successfully, and 100% of capacity retention rate is recorded after 10 000 cycles. This material also shows excellent performances in both acidic (PbO 2 as positive electrode) and neutral (LiMn 2 O 4 as positive electrode) systems. Detailed structural characterizations and theoretical calculations prove that the well-preserved phosphate/nitrogen groups from the CDs precursors can effectively modulate the electronic structure and form electron-rich regions on the electrode Hybrid supercapacitors generally show high power and long life spans but inferior energy densities, which are mainly caused by carbon negative electrodes with low specific capacitances. To improve the energy densities, the traditional methods include optimizing pore structures and modifying pseudocapacitive groups on the carbon materials. Here, another promising way is suggested, which has no adverse effects to the carbon materials, that is, constructing electron-rich regions on the electrode surfaces for absorbing cations as much as possible. For this aim, a series of hi...

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Section: Methodsmentioning

confidence: 99%

Robust Negative Electrode Materials Derived from Carbon Dots and Porous Hydrogels for High‐Performance Hybrid Supercapacitors

et al. 2018

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“…The nearly vertical line for Bi 2 S 3 -BG/W in the low-frequency region indicates high ion mobility in the electrolyte and fast adsorption on the electrode surface. Meanwhile, the lower slopes of this curve in the same region, recorded for Bi 2 S 3 -W and Bi 2 S 3 -EG/W, can suggest diffusion difficulties of ions into the pores of electrode material [18]. The largest semicircle diameter (R ct = 0.80 X) was recorded for Bi 2 S 3 -EG/W, suggesting the high intrinsic resistance of this electrode material and sluggish redox reaction kinetics, which result in a rate capability worse than that of the Bi 2 S 3 -W (0.40 X) and Bi 2 S 3 -BG/W (0.63 X) electrodes.…”

Section: Electrochemical Measurements Of Bi 2 Smentioning

confidence: 65%

“…Recently, metal sulfides, which have slightly higher electrical conductivities than metal oxides, have been shown to be promising candidates for electrochemically active materials in lithium-ion batteries (LIB) and supercapacitors [16][17][18]. One metal sulfide, Bi 2 S 3 , is a layer-structured semiconductor, which crystallizes in an orthorhombic system.…”

Section: Introductionmentioning

confidence: 99%

Solvent-controlled morphology of bismuth sulfide for supercapacitor applications

Miniach

Gryglewicz

2018

J Mater Sci

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In our study, we report a facile solvothermal method for the synthesis of Bi 2 S 3 nanoparticles with unique morphologies using water and mixed solvent systems, such as ethylene glycol/water (1:1, v/v) and butyldiglycol/water (1:1, v/v). Altering the solution mixtures used in the solvothermal synthesis allowed the shape of the Bi 2 S 3 nanoparticles to be controlled. The synthesis of Bi 2 S 3 in water at 150°C for 24 h led to the formation of sphere-like particles 100-300 nm in size. Very uniform spherical nanospheres with diameters from 50 to 90 nm formed when ethylene glycol/water mixture (1:1, v/v) was used as the solvent under the same solvothermal conditions. The butyldiglycol/water mixture promoted the formation of plate-shaped Bi 2 S 3 nanoparticles composed of nanorods. The electrochemical properties of the Bi 2 S 3 samples were determined in a three-electrode cell in 6 mol L -1 KOH using cyclic voltammetry, galvanostatic charging/discharging and impedance spectroscopy. Among the synthesized materials, the Bi 2 S 3 sample obtained in the butyldiglycol/water mixture exhibited a superior capacitive behavior with an outstanding capacitance of 550 F g -1 (at 0.5 A g -1 ), and great cycle stability, which was reflected by a capacitance retention of 87% after 500 charge/discharge cycles. These results demonstrate the high potential of Bi 2 S 3 as an active electrode material for supercapacitors.

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“…The single‐crystalline nature of the product endowed by the oriented growth of hydrothermal condition, considerably improving the electron mobility. Numerous studies have witnessed the desired functions they offered when combined with pseudocapacitive nanomaterials . Generally, the shell layer of pseudocapacitive nanomaterials conformally grows on the core nanoarrays by another facile hydrothermal way .…”

Section: Fabrication Strategies For Nanoarchitectured Current Collectorsmentioning

confidence: 99%

“…Finally, a strong synergistic effect can be achieved for these heterogeneous nanoelectrodes. Figure b exhibits the fabrication process toward hierarchical Ni‐Co‐S@Ni‐W‐O core@shell nanosheet arrays, which combine the advantages of good conductivity of Ni‐Co‐S core and high capacitance of Ni‐W‐O shell, resulting in an outstanding electrochemical performance …”

Section: Fabrication Strategies For Nanoarchitectured Current Collectorsmentioning

confidence: 99%

Review on Nanoarchitectured Current Collectors for Pseudocapacitors

2018

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Supercapacitors are of high importance as electrochemical energy storage devices attributing to their outstanding power performance, excellent reversibility and long cycle life. But meanwhile, they suffer from low energy when compared with batteries. Pseudocapacitive materials with a high theoretical capacitance hold a great promise in boosting the energy storage capability for supercapacitors. The emergence of nanoarchitectured current collectors aims to reach their full potentials in charge storage by addressing the challenging issues such as the intrinsically low electrical conductivity, and the sluggish charging–discharging behavior of most pseudocapacitive materials. This review pays particular attention to the advances of nanoarchitectured current collectors for pseudocapacitors. It first gives an introductory background on the design philosophy for nanoarchitectured current collectors based on the charge storage mechanism in pseudocapacitors and also outlines the consequent design considerations, then summarizes the recent achievements in design, fabrication, and utilization of nanoarchitectured current collectors for pseudocapacitors with representative results presented. A comprehensive overview of the strengths and weaknesses of nanoarchitectured current collectors for pseudocapacitors is also highlighted. At the end, future trends and opportunities associated with nanoarchitectured current collectors for pseudocapacitors are discussed.

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Hierarchical Ni-Co-S@Ni-W-O core–shell nanosheet arrays on nickel foam for high-performance asymmetric supercapacitors

Cited by 104 publications

References 56 publications

Robust Negative Electrode Materials Derived from Carbon Dots and Porous Hydrogels for High‐Performance Hybrid Supercapacitors

Robust Negative Electrode Materials Derived from Carbon Dots and Porous Hydrogels for High‐Performance Hybrid Supercapacitors

Solvent-controlled morphology of bismuth sulfide for supercapacitor applications

Review on Nanoarchitectured Current Collectors for Pseudocapacitors

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